In the world of monoskiing, there are few events more dreaded than the High-Side fall. This fall, also described as a “mouse trap”, slams the skier down the hill. The high impact of this fall typically leaves the skier stunned and shaken. Sometimes the result is shoulder dislocation, head injury, or worse.
No monoskier is immune to the High-Side fall. But there is a subset of monoskiers who are at high risk of this occurrence. These monoskiers are typically novice, higher-level spinal cord injury with minimal trunk control who are insufficiently supported by their seating system, and who have outriggers that are too short. This combination of factors is likely to lead to instances of Reverse-Angulation which inevitably results in a High-Side fall. While Reverse-Angulation is NOT the only configuration that creates a High-Side fall, it is a primary cause among the previously described group.
If you google the term “Reverse-Angulation”, you will notice that it isn’t described in any skiing literature. Able-bodied skiers don’t engage in Reverse-Angulation because it is so intuitively incorrect. It feels wrong. They do something else because they can. Monoskiers with sufficient trunk control also quickly learn to counter Reverse-Angulation with their trunk muscles. Once they recognize this positional configuration and its negative ramifications, they naturally learn to avoid and counter it.
Unfortunately, Reverse-Angulation is the likely experience of a novice monoskier who has not yet learned to balance and control the ski’s edge due to the combination of insufficient seating support and short outriggers. Imagine a child riding a bike with training wheels. The bike falls side-to-side as the child pedals, it is kept from falling over by its training wheels. When the child turns, the bike due to centrifugal force, tips to the outside of the turn. The child instinctively leans into the turn in order to prevent from tipping over to the outside of the turn. This position is Reverse-Angulation.
In above example, Reverse-Angulation is created by the child’s mechanical inability to sufficiently Inclinate (bank) the bicycle into the turn due to the presence of the inside training wheel. When the bike tips to the outside of the turn, and if the speed is not too great, an equilibrium of Reverse-Angulation is created. The bike leans out, the child leans in. It looks and feels awkward, but no fall results. Reverse-Angulation is not seen in balanced bicycling because, this configuration is inherently unbalanced. Its existence denotes a fall. In fact, a photo snapshot of a bicyclist who falls to the outside of a turn is likely to show the Reverse-Angulation position as their last ditch, instinctive and fruitless attempt to counter the fall. In summary, experienced bicyclists don’t Reverse-Angulate. Novice bicyclists with training wheels do.
The outriggers used by novice monoskiers create a similar effect as training wheels on bicycles. The outriggers are used to hold up the unbalanced monoskier. The outriggers initiate the unbalanced turning from a relatively flat ski position. Sensing the impending fall, the lack of trunk control monoskier desperately tries to avoid it by leaning their head and shoulders up the hill. This is an instinctive reaction that is very difficult to counter because they have no other effective alternative. In this unbalanced state (turning/sliding sideways on a flat ski) leaning down the hill will likely result in an immediate High-Side fall. Instinct and life experience tells the novice monoskier to lean into the hill when at-risk of falling down the hill. Thereby creating the ugly - Reverse-Angulation.
Monoskiers who repeatedly experience Reverse-Angulation have usually been instructed that they need to “lean down the hill” to avoid High-Side falls. This advice needs to be prefaced with, “if you are on a balanced ski”. But if you are not on a balanced ski, then it doesn’t make on-the-spot sense to lean down the hill, especially when you have short outriggers which will not hold you up in a position of balance. You lean up the hill, like the child turning the bicycle with training wheels, because it makes sense at that moment in time as a means to try to avoid the downhill fall. On the other hand, a monoskier with trunk control will soon lean to drive their hip into the hill. They have two choices, lean up the hill and create Reverse-Angulation or use their lower body position to create Angulation. It doesn’t take them long to learn to choose Angulation (except in moments of fear and panic).
High angulation is the holy grail of carved turns for monoskiing (Dynamic Skiing). It is the configuration of high ski edge angle which enables high speed (racing style) turns where the skier can be seen leaning down the hill. The ski edge literally cuts a trench in the ski slope as the monoskier zooms down the mountain. The monoski is balanced (like a cornering bicycle) on its ski edge. The outriggers don’t act as training wheels, they are like the balancing pole of a high-wire walker. They enable turn initiation and enhance balancing.
There is also Inclination. This configuration occurs when a monoskier with a rigid upper body support system banks the entire monoski up the hill which has the effect of putting the ski on its edge. Inclination differs from Reverse-Angulation by the lack of hinging (trunk bending). The movement of hinging enables both desirable Angulation and the dreaded Reverse-Angulation. In fact, the body configuration of Reverse-Angulation is the same as Angulation IF the monoskier was turning in the opposite direction at that moment. If you mechanically restrict the possibility of Reverse-Angulation, you restrict Angulation to the exact same degree, and you will get Inclination.
Inclination is created by either falling up the hill (gravity is the initiator), or purposely using your downhill outrigger to lean (push) you and your monoski up the hill. Imagine the child with training wheels dropping his outside foot and pushing his bike over to cause it to lean inside the turn. If his leg is too short, he can’t do it. If your outriggers are too short, and you have minimal truck muscles, you can’t push your monoski over to create a banked edge angle. You will likely end up briefly holding your monoski (somewhat vertical) before your flat ski catches an edge and you High-Side fall. Ouch!
Inclination doesn’t create the carved turns because the resulting edge angle and edge pressure is not sufficient. It creates functional skidding style turns (Static Skiing). It is less likely to result in High-Side falls than Reverse-Angulation, but more likely to High-Side than Angulation. To summarize: Angulation is Good! Inclination is Not-So-Good. Reverse-Angulation is Ugly! If you are a monoskier with minimal trunk control and you are repeatedly High-Side falling, you are likely experiencing Reserve-Angulation. Your seating system is probably not providing you with sufficient trunk support, and/or your outriggers are too short. It’s not your fault. It’s not that you “haven’t quite figured it out”. Or that you just need to do XYZ when skiing. You need a proper skiing setup, and you don’t have it, yet.
This is an excellent article and explanation of what creates the dreaded head slapping down hill edge catch fall we see in novice mono skiers. The author calls it the "mousetrap," I've always called it the "Flyswatter" with massive angular acceleration of the upper body around the pivot point of the downhill edge catching, especially in a high speed side slip. I agree with the fact that this tends to happen most frequently when the riggers are too short; but I've also seen it happen even when the riggers are properly adjusted and long (for a beginner). When I see this type of fall it is either for the reasons the author mentions OR from a failure of the …